Artículo de revista
The Hercules stream as seen by APOGEE-2 South
Fecha
2018Registro en:
Monthly Notices of The Royal Astronomical Society 474, 95–101 (2018)
10.1093/mnras/stx2777
Autor
Hunt, Jason A. S.
Bovy, Jo
Pérez Villegas, Angeles
Holtzman, Jon A.
Sobeck, Jennifer
Chojnowski, Drew
Santana, Felipe A.
Palicio, Pedro A.
Wegg, Christopher
Gerhard, Ortwin
Almeida, Andres
Bizyaev, Dmitry
Fernández Trincado, Jose G.
Lane, Richard R.
Longa Peña, Penélope
Majewski, Steven R.
Pan, Kaike
Roman Lópes, Alexandre
Institución
Resumen
The Hercules stream is a group of comoving stars in the solar neighbourhood, which can potentially be explained as a signature of either the outer Lindblad resonance (OLR) of a fast Galactic bar or the corotation resonance (CR) of a slower bar. In either case, the feature should be present over a large area of the disc. With the recent commissioning of the APOGEE-2 Southern spectrograph we can search for the Hercules stream at (l, b)=(270 degrees, 0), a direction in which the Hercules stream, if caused by the bar's OLR, would be strong enough to be detected using only the line-of-sight velocities. We clearly detect a narrow, Hercules-like feature in the data that can be traced from the solar neighbourhood to a distance of about 4 kpc. The detected feature matches well the line-of-sight velocity distribution from the fast-bar (OLR) model. Confronting the data with a model where the Hercules stream is caused by the CR of a slower bar leads to a poorer match, as the corotation model does not predict clearly separated modes, possibly because the slow-bar model is too hot.
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